1. Field of Invention
The present invention relates to a nonroad engine, and more particularly to an exhaust filter system for a diesel/gasoline nonroad engine for such as a generator, which substantially removes harmful substances of exhaust gases from the generator.
2. Description of Related Arts
Conventional generator generally includes a nonroad internal combustion engine comprising a crankshaft, and a fuel reservoir for supplying fuel to the internal combustion engine in such a manner that when the fuel is ignited in the internal combustion engine to complete a combustion process, the crankshaft is driven to rotate for producing mechanical power. Therefore, by incorporating an induction rotor with the internal combustion engine, the mechanical rotational force produced by the internal combustion engine is transformed into a motional electromotive force through a magnetic force provided by the induction rotor so as to convert into an electrical energy.
Generally speaking, there are two types of nonroad engine, which are diesel engine and gasoline engine, commonly used. Since the compression ratio of the diesel engine is higher than that of the gasoline engine, the diesel engine is usually more efficient than the gasoline engine. However, both diesel and gasoline engines have a common drawback.
Due to the inefficiency of fuel ignition in the nonroad engine, the resulting incomplete combustion of the fuel, especially for the diesel engine, leads to carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC) in the exhaust gas that contributes to air pollution. Therefore, in order to market the nonroad engines and generators in the United States, the exhaust gas of the nonroad engine must meet the exhaust certification standard (STD) and certification levels (CERT) for hydrocarbon (HC), oxides of nitrogen (NOx), or non-methane hydrocarbon plus oxides of nitrogen (NMHC=NOx), carbon monoxide (CO, and particular matter (PM) in grams per kilowatt-hour (g/kW-hr), and the opacity-of-smoke certification standards and certification levels in percent (%) during acceleration (Accel), lugging (Lug), and the peak value from either mode (Peak) for this engine family (Title 13, California Code of Regulations, (13 CCR) Section 2423) of the United States Environmental Protection Agency and the state agency such as California Air Resources Board.